I understand the concern about the oil bath rearing conversion. From what I have found from local boat and rv trailer shops the oil baths are more reliable and easy to check for oil level thru the cover and can be filled easily. If you have questions contact ETrailer they respond fairly quick...
I have a HQ15 Black Series travel trailer and I am in the process of converting the hubs to an oil bath bearing set up. Due the amount of miles traveled and weight #5200. From what I been advised its good solution to the joys bearing packing...
I have a ATI damper on my Barracuda. I used a pre ‘69 two grove crank pulley (they are 1/2” shorter) to align with the ‘70 and up pulleys. The main problem was having the machinist hone it to fit.